The 3rd Generation Partnership Project (3GPP) has launched, based on existing 2nd generation (2G) mobile communications and 3rd generation (3G) mobile communications networks, an evolved packet system (EPS). An EPS network includes an evolved universal mobile telecommunications system territorial radio access network (E-UTRAN) and an evolved packet core network (EPC network). At an early stage of an EPS network construction, an operator has already had a mature circuit switched (CS) network; however, the EPS network processes only a packet switched (PS) service. For protection of CS network investment and a deployment policy of the EPS network, the operator may use an original CS mobility management device to provide a CS service. To meet this requirement, 3GPP extends a function of a Gs interface between a mobile switching center/visitor location register (MSC/VLR) and a serving GPRS support node (SGSN) that are in the existing 2G or 3G network, and defines an SGs interface between the MSC/VLR and a mobility management entity (MME) in the EPC network, where GPRS is short for general packet radio service. Based on a function of the SGs interface, 3GPP proposes a “circuit switched fallback” (CSFB) technology and a short message service message over SGs (SMS over SGs) technology. By means of the CSFB technology, a user equipment (UE) covered by an E-UTRAN falls back to a CS domain in the 2G/3G network by using the E-UTRAN when a CS voice service needs to be processed, so as to complete processing of the CS voice service. By means of the SMS over SGs technology, the UE that resides in the E-UTRAN reuses an existing CS domain device to implement transmission of a short message service message in the CS domain.
To greatly reduce heavy deployment costs of a radio access network for an operator, 3GPP proposes a network sharing idea, i.e., public land mobile networks (PLMN) of multiple operators or multiple PLMNs of one operator can share a same radio access network to provide a wireless communication service. For the CSFB technology and the SMS over SGs technology, an operator also proposes a requirement for CS domain network sharing, which mainly has the following two scenarios:
Scenario 1: A conventional operator upgrades an existing CS domain network (including a 2G network and a 3G network), to support the CSFB technology and the SMS over SGs technology, i.e., the operator can provide, by sharing multiple PLMNs operated by the operator or sharing a PLMN of another operator by signing a roaming agreement, a CS service for a UE that resides in an E-UTRAN.
Scenario 2: An operator who provides an emerging pure PS service leases a CS domain network from a conventional operator by signing an agreement, to support the CSFB technology and the SMS over SGs technology.
In the foregoing scenarios of CS domain network sharing, multiple available PLMNs may provide a CS service for a same UE that resides in an E-UTRAN. During a combined attach procedure or a combined tracking area update procedure that is initiated by the UE, if multiple available PLMNs provides a CS service for the UE, an MME selects a proper PLMN according to a PLMN, location information of a tracking area in which the UE is currently located, and a CS domain network selection policy of an operator, where the PLMN, the location information, and the CS domain network selection policy are reported by an evolved NodeB (eNB). Based on the selected PLMN and the location information of the tracking area in which the UE is located, a corresponding CS domain location area identity (LAI) is allocated to the UE, and an associated MSC/VLR is selected based on the LAI. After the combined attach procedure is complete, the UE receives an attach accept message sent by the MME, where the attach accept carries a tracking area identity list (TAI list), a LAI, and a VLR temporary mobile subscriber identity (TMSI). For the UE, that the UE acquires the LAI and the VLR TMSI indicates that CS domain attaching is successful.
After the combined attach procedure is complete, the UE succeeds in registering with a network of an operator, and the UE needs to display a name of the registered network. Alternatively, after the combined tracking area update procedure, the UE needs to display a name of a registered network. Currently, the UE displays a network name mainly based on two policies.
Policy 1: A network side does not perform configuration, and the UE displays a network name according to a configuration of the UE.
Specifically, the UE displays, according to a PLMN identity (ID) of a currently registered network, a network name corresponding to the PLMN ID.
However, in some scenarios, the UE cannot determine which network name, corresponding to a PLMN ID, to display.
Policy 2: The network side delivers a to-be-displayed network name to the UE.
When receiving a network name delivered by the network side, the UE may use the received network name to update a network name configured by the UE, and display the updated network name.
(1) The MME informs the UE of the to-be-displayed network name by using an E-UTRAN mobility management information (EMM information) message, and the UE displays the informed network name, where the network name informed by the MME is determined by the MME according to a home PLMN (HPLMN) of the MME.
(2) An MSC/VLR delivers a network name of a CS domain network, with which the UE registers, to the MME through an SGs interface. The MME informs the UE of the to-be-displayed network name by using the EMM Information message, and the UE displays the informed network name, where the network name informed by the MME is a network name that is of the HPLMN of the MME and is determined by the MME according to a policy of the MME, or is a network name of the CS domain network with which the UE registers by using the MSC/VLR.
However, in the policy in which the network side delivers a network name to the UE for displaying, in some scenarios, the UE cannot determine a to-be-displayed network name, and the MME does not learn which network name is displayed on the UE either.